National Institute
on Alcohol Abuse and Alcoholism No.
46 December
1999

Are Women More Vulnerable
to Alcohol's Effects?

Women appear to be more vulnerable than men to many adverse consequences
of alcohol use. Women achieve higher concentrations of alcohol in the blood
and become more impaired than men after drinking equivalent amounts of alcohol.
Research also suggests that women are more susceptible than men to alcohol-related
organ damage and to trauma resulting from traffic crashes and interpersonal
violence. This Alcohol Alert examines gender differences in alcohol's
effects and considers some factors that may place women at risk for alcohol-related
problems.

Prevalence of Women's
Drinking

Household surveys indicate
that alcohol use is more prevalent among men than women in the United States
(1,2). In one survey, 34 percent of women reported consuming at least 12 standard
drinks1 during the previous year compared with 56 percent of men
(1). Among drinkers surveyed, 10 percent of women and 22 percent of men consumed
two or more drinks per day on average (1). Men are also more likely than women
to become alcohol dependent (3).2

Women's drinking is
most common between ages 26 and 34 and among women who are divorced or separated
(2). Binge drinking (i.e., consumption of five or more drinks per occasion
on 5 or more days in the past month) is most common among women ages 18 to
25 (2). Among racial groups, women's drinking is more prevalent among whites,
although black women are more likely to drink heavily (1).

Metabolism

Women absorb and metabolize
alcohol differently than men. In general, women have less body water than
men of similar body weight, so that women achieve higher concentrations of
alcohol in the blood after drinking equivalent amounts of alcohol (5,6). In
addition, women appear to eliminate alcohol from the blood faster than men.
This finding may be explained by women's higher liver volume per unit lean
body mass (7,8), because alcohol is metabolized almost entirely in the liver
(9).

Consequences of
Alcohol Use

Research suggests that
women are more vulnerable than men to alcohol-related organ damage, trauma,
and legal and interpersonal difficulties.

Liver Damage.Compared with men, women develop alcohol-induced liver disease over a
shorter period of time and after consuming less alcohol (10,11). In addition,
women are more likely than men to develop alcoholic hepatitis and to die from
cirrhosis (12). Animal research suggests that women's increased risk for liver
damage may be linked to physiological effects of the female reproductive hormone
estrogen (13).

Brain Damage.
Views of the brain obtained by magnetic resonance imaging (MRI) suggest
that women may be more vulnerable than men to alcohol-induced brain damage.
Using MRI, researchers found that a brain region involved in coordinating
multiple brain functions was significantly smaller among alcoholic women compared
with both nonalcoholic women and alcoholic men. These differences remained
significant after measurements were adjusted for head size (14). Conversely,
a study measuring metabolic energy utilization in selected brain regions found
a significant difference between alcoholic and nonalcoholic men but no significant
difference between alcoholic and nonalcoholic women (15). These results are
not consistent with a greater vulnerability to alcoholic brain damage in women.
However, the female alcoholics reported less severe alcohol use compared with
the male alcoholics studied (15).

Heart Disease.Men and women who consume oneor two alcoholic drinks per day have
a lower death rate from coronary heart disease (e.g., heart attacks) than
do heavier drinkers and abstainers, as discussed in Alcohol Alert No. 45,
"Alcohol and Coronary Heart Disease" (16). Among heavier drinkers, research
shows similar rates of alcohol-associated heart muscle disease (i.e., cardiomyopathy)
for both men and women, despite women's 60 percent lower lifetime alcohol
use (17).

Breast Cancer.Many studies report that moderate to heavy alcohol consumption increases
the risk for breast cancer (18), although one recent study found no increased
breast cancer risk associated with consumption of up to one drink per day,
the maximum drinking level reported by most women (19).

Violent Victimization.A survey of female college students found a significant relationship between
the amount of alcohol the women reported drinking each week and their experiences
of sexual victimization (20). Another study found that female high school
students who used alcohol in the past year were more likely than nondrinking
students to be the victims of dating violence (e.g., shoving, kicking, or
punching) (21).

A history of heavy
premarital drinking by both partners has been found to predict first-year
aggression among newlyweds (22). In some studies, problem drinking by wives
has been linked to husband-to-wife aggression regardless of the husbands'
drinking levels (23).

Traffic Crashes.Although women are less likely than men to drive after drinking (1,24)
and to be involved in fatal alcohol-related crashes (25), women have a higher
relative risk of driver fatality than men at similar blood alcohol concentrations
(26).Laboratory studies of the effects of alcohol on responding to
visual cues and other tasks suggest that there may be gender differences in
how alcohol affects the performance of driving tasks (27).

Women's lower rates
of drinking and driving may be attributed to their lower tendency toward risk
taking compared with men (28,29). Women are also less likely to view drinking
and driving as acceptable behavior. In a 1990 national household survey, 17
percent of women,compared with 27 percent of men, agreed that it was
acceptable for a person to drink one or two drinks before driving (30). Nevertheless,
the proportion of female drivers involved in fatal crashes is increasing.
In 1996, 16 percent of all drivers involved in alcohol-related fatal crashes
were women, compared with 13 percent in 1986 and 12 percent in 1980 (25).

Risk Factors for
Women's Alcohol Use

Factors that may increase
women's risk for alcohol abuse or dependence include genetic influences, early
initiation of drinking, and victimization.

Genetic Factors.The relative contribution of genetic factors to women's risk for alcoholism
has been debated. A survey of 2,163 female twins revealed greater similarity
between identical twins compared with fraternal twins on measures of alcohol
consumption (31). Similar studies including more than 12,000 twin pairs from
the general population have confirmed that among both male and female twin
pairs, identical twins are more likely than fraternal twins to have similar
rates of alcohol dependence, alcohol abuse, and heavy alcohol consumption
(32,33).

Studies of women who
had been adopted at birth have shown a significant association between alcoholism
in adoptees and their biologicalparents (34). In addition, antisocial
personality (e.g., aggressiveness) in biological parents may predict alcoholism
in both male and female adoptees (35). However, potential interactions between
genetic and environmental influences require further study.

Age of Initiating
Drinking.Results of a large nationwide survey show that more than
40 percent of persons who initiated drinking before age 15 were diagnosed
as alcohol dependent at some point in their lives (37). Rates of lifetime
dependence declined to approximately 10 percent among those who began drinking
at age 20 or older. The annual rate of this decline was similar for both genders
(37). Although in the past women generally started drinking at later ages
than men, more recent survey data show that this difference has nearly disappeared
(2).

Victimization.Using data collected in a large general population survey, Wilsnack and
colleagues (38) found that women who reported being sexually abused in childhood
were more likely than other women to have experienced alcohol-related problems
(e.g., family discord or household accidents) and to have one or more symptoms
of alcohol dependence. Another study found that women in alcoholism treatment
were significantly more likely to report childhood sexual abuse and father-to-daughter
verbal aggression or physical violence compared with women in the general
population (39).

Widom and colleagues
(40) reached a different conclusion from that of Miller and colleagues. Instead
of relying on women's recall of their pasts, Widom and colleagues consulted
court records to identify cases of childhood physical or sexual abuse. These
researchers found that for women, a history of childhood neglect, but not
abuse, significantly predicted the number of alcohol-related symptoms experienced,
independent of parental alcohol or other drug (AOD) problems, childhood poverty,
race, and age.

Physical abuse during
adulthood has also been associated with women's alcohol use and related problems.
One study found that significantly more women undergoing alcoholism treatment
experienced severe partner violence (e.g., kicking, punching, or threatening
with a weapon) compared with other women in the community. In addition, among
women in the community group, those with AOD-related problems reported significantly
higher rates of severe partner violence than women without such problems.
Although the findings indicate that partner violence and AOD problems co-occur
among women, the data do not indicate whether the association is causal (41).

As can be seen by the
varied types of information reported on in this Alcohol Alert, the
alcohol research field has begun to recognize the importance of understanding
gender differences in how alcohol is used, in the consequences of alcohol
use, and in the development of alcohol dependence. For example, where women
and men drink at the same rate, women continue to be at higher risk than are
men for certain serious medical consequences of alcohol use, including liver,
brain, and heart damage. We know that some of this risk is due to gender differences
in metabolism; it also could quite possibly be due to gender-related differences
in brain chemistry, in genetic risk factors, or to entirely different factors
that are currently unknown. The more science can tell us about gender-related
aspects of alcohol-related problems-not only what they are but why-the better
job we will be able to do to prevent and treat those problems in all populations.